I did training prior to deployment overseas into a conflict zone, and benefited from instructors who had already been over there and seen some of the worse it had to offer. I could see that an instructor who both specialized in a topic and had outlier experience within it as being ideal. You could even just say it's actual experience, the reality-checking of theory, no different from how you might benefit learning software dev from a prof who had been a SE at some point. It's the difference between learning from someone who's only read about a topic in books vs. actually done the thing. Kinetic combat (like software development) is one of those topics that the actual reality diverges from media depictions, so that grounding in the real is why you train for it in the first place.
Neutralizing threats in an intense situation requires split-second decision-making. These decisions will be scrutinized after the fact, possibly for years, so the purpose of such training is largely to hardwire the correct action into reflex.
Hardly an excuse... since it is a deadly device, perhaps said plate should be optimized to emphasize gun training/safey.
Although I suppose that won't help with people that are just trigger-happy.
The culture war is the politics. It's all very post social media swerve into conspiracy theories.
What is clear is that the CBP agents had already taken Pretti's legally carried firearm from him at this point. So it is no difference if the CBP employee caused the gun they took to fire or if all shots were directly into the back of Pretti as he lay on the ground. In both cases it was a murder caused entirely by their actions and stupidity.
And there still has not been any investigation, any indictment, or a fair trial. We are not living in a nation of laws. This terrible CBP "training" by the violent criminal David Norman this wired article highlights is part of it.